* Populate SDP cid in track info when available.
- Adding SDP cid to TrackInfo. Browsers like FF uses a different stream
id for AddTrack and actual SDP offer. So, have to look up using both
on server side. To make it easier, store both (only if different) in
TrackInfo.
- Use a codec in TrackInfo for audio also. There is some discussion
around doing simulcast codec for audio so that something like PSTN can
use G.711 without any transcoding. So, just keep it consistent between
audio and video.
- Populate SDP cid when SDP offer is received. It could populate a
pending track or an already published track if the new offer is for a
back up codec where the primary codec is already published.
- Passed around parsed offer to more places to avoid parsing multiple
times.
- Clean up MediaTrack interface a bit and remove unneeded methods.
* WIP
* WIP
* deps
* stream allocator mime aware
* clean up
* populate SDP cid before munging
* interface methods